1998 Honda Civic AC problem

howdy. My ac is on the fritz. In the morning 8am-10am and during the night 9pm and later my ac blows cold air. During the day 11am-7pm it blows warmish air. Sometimes it blows cool air during the day and sometimes it doesnt. It seems to go in out during the day. Had the system recharged last year about July and worked fine until about this July. Now it works when is wants. Any suggestions?